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As people age, physical and cognitive changes that are part of the normal aging process can affect their ability to drive safely. These changes include:

  • Declines in Functional Ability. Drivers’ overall functional abilities decline as their physical, visual, and cognitive capabilities diminish with age. Physical capabilities including hearing, muscle tone, reaction time, and visual capabilities (especially vision at night) all decline, albeit at very different rates on the individual level. The state of current research on visual scanning ability and availability of training programs for visual scanning skills has been summarized in a 2018 NHTSA report (Lococo & Staplin). Cognitive capabilities can also diminish. Driving is a complex activity that requires a variety of high-level cognitive skills that can diminish through changes that occur with normal aging or because of dementia. Merickel et al. (2019) found that drivers with greater cognitive dysfunction displayed more erratic braking and accelerating behaviors in certain conditions such as daytime and on interstates. As drivers get older, they tend to be overrepresented in crashes requiring navigation of more complex situations such as intersections, left turns, and reacting to an impending crash (Stutts et al., 2009). That said, mild cognitive decline can still allow for safe driving (Staplin et al., 2019). Overall, tests of functional ability to drive may provide better indicators of crash risk.
  • Increased Medication Use. Over 90% of older drivers take prescription medications (Rosenbloom & Santos, 2014). These medications alone or in combination with other medications may be necessary to control disease or health conditions, but also may cause drowsiness or otherwise affect driving.
  • Driving Errors. Older drivers are less likely to drive aggressively or speed. However, they may exhibit other risky behaviors, such as driving more slowly than prevailing traffic or failing to detect or accurately judge the speed of an oncoming vehicle while making an unprotected left turn. The most frequent driving errors made by older adults include the failure to yield right-of-way (Mayhew et al., 2006), inadequate surveillance, and misjudgment of gaps (Cicchino & McCartt, 2015). Older adults are more likely to be involved in angle collisions, overtaking- and merging-related collisions, and crashes in intersections (Lombardi et al., 2017).

Driver behaviors also change with age. Some of these changes may help protect the driver from serious injury and crashes. These behaviors include:

  • Decreased Impaired Driving. Older drivers are less likely than younger drivers to be involved in alcohol-related crashes (Stutts et al., 2009).
  • Limit Setting. Many older drivers recognize and avoid driving at times and in places they feel uncomfortable, such as at night, on high-speed roads, or in unfamiliar situations (Staplin & Lococo, 2003). Older drivers are underrepresented in nighttime crashes, probably due in part to their limited nighttime driving (Stutts et al., 2009). Evidence suggests that drivers who avoid situations such as bad weather, poor visibility, and complex parking procedures may be experiencing declines in their driving skills (Schulz, 2019). However, the synthesis of self-regulation literature conducted by Molnar et al. (2015) indicates that factors aside from awareness of changes in functional ability (such as reduced need to travel, increased schedule flexibility, and general feelings of discomfort) also contribute to limit setting. While older adults drive fewer miles annually than younger drivers, the 2017 National Household Travel Survey indicates that older drivers spend more time driving and take more trips than previous cohorts of older drivers (Pomidor, 2019).
  • Seat Belt Use. Seat belts are even more effective in preventing injuries and fatalities to older than to younger occupants (Potts et al., 2004). While belt use among older occupants is slightly higher than the national average—91.7% for occupants 70 and older compared to the overall national estimate of 90.7% in 2019 (Enriquez, 2020)—the fact remains that about 8% of older occupants are unbelted. Communications and outreach on the benefits of seat belt use may be more effective with older occupants because they may be more attentive to health and safety issues. In one study, for example, signs urging seat belt use resulted in a substantial increase in belt use in six senior communities compared to controls, and use remained higher after 4 years (Cox et al., 2005). For more information on countermeasures to increase seat belt use, see Chapter Seat Belts and Child Restraints.

As a result of many of the changes and differences referenced above, the fatal crash involvement rate for drivers 65 and older is lower than for drivers younger than 65.

Driver Involvement in Fatal Crashes per 100,000 Licensed Drivers - 2021

Source: NHTSA (2023)

However, since older drivers drive fewer miles annually compared to younger drivers, the fatal crash rate alone does not accurately describe the risk. The average fatal crash rate per mile traveled is higher for drivers 70 and older than for all age groups except drivers 16 to 19 (IIHS, 2023). Unfortunately, the fatal crash rate per mile traveled is also imperfect as older drivers tend to favor local roads that, while are typically lower speed, include more points of potential hazards. Additionally, older adults experience increased fragility and frailty. Fragility, as measured by deaths per drivers involved in crashes, begins to increase at age 60 and rises steadily with advancing age. Older occupants, including drivers, are more likely to sustain a serious injury or fatality than younger occupants. Frailty can also cause long-term health issues that make it difficult for older driver and occupants to recover from injury. Fragility, rather than an increased tendency to get into crashes, accounts for about 60% to 95% (depending on age group and sex) of the increased fatality rates per miles traveled in older drivers (Li et al., 2003).

Of all the subject areas in this countermeasure guide, those related to older drivers are perhaps the most complex because they involve so many issues beyond traffic safety. Driving cessation can have a substantial effect on an older adult’s mobility and on physical and mental health. Sooner or later, in the interest of safety, most older people must restrict or cease driving, either by choice or as the result of the State licensing authority restricting or revoking their license. SHSOs and licensing agencies are encouraged to plan and implement their older driver policies and programs as part of integrated community activities to improve older people’s safety, mobility, and health.